GOLD Mission’s Observation about the Geomagnetic Storm Effects on the
Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma
Bubbles (EPB) During a Solar Minimum Equinox
Abstract
The nighttime ionospheric response to a geomagnetic storm occurred on
23-29 September 2020 is investigated over the South American, Atlantic,
and West African longitude sectors using NASA’s Global-scale
Observations of the Limb and Disk (GOLD) measurements. On 27 September
the solar wind conditions were favorable for prompt penetration electric
fields (PPEF) to influence the equatorial ionosphere over extended
longitudes. The equatorial ionization anomaly (EIA) crests were shifted
8o-10o poleward compared to the
quiet time monthly mean across ~65o-
35oW during the main phase. Ionosonde hmF2 (peak
electron density height) measurements from Fortaleza (GG:
-3.9oN and -38.4oW) indicated a
stronger prereversal enhancement this evening than other nights. As a
result, Equatorial Plasma Bubbles (EPB) occurred at these longitudes on
this evening. This is the first simultaneous investigation of EIA
morphology and EPB occurrence rate over an extended longitude range from
geostationary orbit during a geomagnetic storm.